Product specifications
9/22
XC9220/XC9221
Series
● Output Voltage Setting
Output voltage can be set by adding split resistors. Output voltage is determined by the following equation, based on
the values of R
FB1 and RFB2. The sum of RFB1 and RFB2 should normally be 1MΩ or less.
V
OUT = 0.9 x (RFB1 + RFB2) / RFB2
The value of C
FB, speed-up capacitor for phase compensation, should be adjusted by the following equation. Fzfb
should usually be 5kHz. Adjustments are required from 1kHz to 20kHz depending on the application, value of
inductance (L), and value of load capacity (C
L
).
CFB = 1 / (2 x
π
x RFB1 x fzfb)
[Sample calculation: Setting 3.3V V
OUT]
RFB1 = 200k
Ω
, RFB2=75k
Ω
, VOUT = 0.9 x (200k + 75k) / 75k = 3.300V
C
FB = 1 / (2 x
π
x 200k x 5k) =150pF
[Typical examples]
VOUT
(V)
RFB1
(kΩ)
RFB2
(kΩ)
CFB
(pF)
VOUT
(V)
RFB1
(kΩ)
RFB2
(kΩ)
CFB
(pF)
1.2 100 300 330 3.3 200 75 150
1.5 180 270 180 5.0 150 33 220
1.8 220 220 150 12.0 160 13 180
IOUT UP TO 500mA UP TO 1A UP TO 2A UP TO 3A
P-ch MOSFET (*1)
CPH3308
(SANYO)
2SJ616
(SANYO)
2SJ646
(SANYO)
Schottky Barrier Diode
(SBD) (*2)
XB01SB04A2BR
(TOREX)
D1FH3 (SHINDENGEN)
CMS02 (TOSHIBA)
DE5PC3
(SHINDENGEN)
*1: Recommended to use P-ch MOSFET with Ciss less than 1500pF.
*2: SBD should be used with high-toned reverse characteristics.
OUTPUT VOLTAGE
RSENSE (mΩ)
V
OUT
≦2.5V
100
V
OUT
>2.5V 50
● Recommended MOSFET and SBD (Examples)
● Ceramic Capacitor
With the XC9220/9221 series, a ceramic capacitor can be used as an output capacitor (C
L
). RSENSE resistor
is required for using the ceramic capacitor. The value of RSENSE resistor is determined depending on the
setting output voltage as the chart below.
＜External Components＞
P-ch MOSFET: 2SJ646 (SANYO)
SBD: DE5PC3 (SHINDENGEN)
L: CDRH8D28-4R7 (4.7μH, SUMIDA / fosc=1.0MHz)
CDRH8D43-100 (10μH, SUMIDA / fosc=500kHz)
CDRH127-220 (22μH, SUMIDA / fosc=300kHz)
CIN: 22μF (ceramic)
CL: 22μF (ceramic / fosc=1.0MHz, 500kHz)
47μF (ceramic / fosc=300kHz)
RSENSE: 100mΩ (V
OUT≦2.5V)
50mΩ (V
OUT＞2.5V)
■OPERATIONAL EXPLANATION
(
Continued
)